(a) Field of the Invention
The present invention relates to an improvement of a sensor switch, and particularly to the formation of a panel system sensor switch used for a write input means or a sensor switch useful for a thin key board means to perform an input by pressing down the upper surface of the switch with fingers or with another kind of pressing-down jig.
(b) Description of the Prior Art
Conventionally, a handwrite input means for personal computers is known as one of the write input means of the most simple formation. A sheet sensor switch panel used for this kind of input means is formed by so piling two sheets of polyester film uniformly applied with a carbon resistance body that the resistance bodies are facing each other by interposing therebetween micro dot-like spacers made of resin. The dots to be the spacers are protrusions of approximately 0.5 mm in diameter and approximately 50 .mu.m in height and a number of them are integrally arranged on either surface of two sheets of polyester film facing each other with the spacing of approximately 5 to 6 mm.
By the way, in such formation, the root portion of dots will sink concavely because of fatigue when a write-in operation is repeated and, consequently, it has such a defect that mis-action is easy to happen through the contact of faced two resistance films caused even by the small vibration or the variation of temperature.
In case that the spacing between the dots adjacent each other is, for example, made so small as of 2.5 to 3 mm to improve this defect, a large pressing-down force will be necessary during the write-in operation. This will not only reduce the operability but also increase the fatigue of the surface of contact and it will result in the deterioration of the conductive performance.
Further, in this type of formation, because the distortion caused by the small variation of sizes and/or the temperature variation will come out as a bending of film face, there is a defect that a mis-action or short-circuit is easy to happen. Moreover, in a conventional formation, as the circumference of the root of dot is more difficult to deform than other parts, there is a defect that is not easy to elevate an input resolution.